Adipose tissue islets: tissue culture of a potential source of fat cells in the adult rat.
Collagenase digests of adipose tissue of the 3 to 4-month-old rat contain groups of 20-100 tightly arranged cells (islets) that copurify with the free-floating fat cells. When cultured along with mature adipocytes the islets give rise to cells, initially fibroblast-like, which rapidly proliferate, acquire lipid droplets, and differentiate into small adipocytes within 4-6 days without the addition to the medium of the agents usually required to produce differentiation in stromal-vascular preadipocytes. Differentiation of these cells is independent of confluence and begins as early as day 2 of culture. The proportion of islet-derived cells that differentiate is directly correlated with the number of mature adipocytes simultaneously present in the culture (r = .709; P less than 0.001). Culture medium exposed to mature adipocytes demonstrated differentiation-promoting activity, suggesting a paracrine effect of these cells. Islets may in vivo constitute a source for newly formed adipocytes in the adult rat. The differentiation of these potential adipocytes may be regulated, at least in part, by the mature fat cells via a paracrine effect.
Carraro
R
R
Gerontology Research Center, National Institute on Aging, National Institutes of Health, Francis Scott Key Medical Center, Baltimore, Maryland 21224.
Lu
Z D
ZD
Li
Z H
ZH
Johnson
J E
JE
Gregerman
R I
RI
D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011916:Rats, Inbred F344; D013234:Stem Cells / Q000166:cytology